Oh boy, I could write a PhD dissertation on this. I'll boil it down to a handful, in no particular order:
1 - The "slightly turned baseball cap" fad from a few years ago.
2 - Current women's (girls?) fashion trend of the high-waisted shorts that are pulled as far up their *** as possible. This doesn't look comfortable nor is it doing anything to make your back side look smaller.
3 - Fidget spinners...don't get me started
4 - Any sort of pop music.
5 - This is the biggest of them all: when people use "adult" as a verb. "Paid my rent, washed the dishes, did the laundry, and bought groceries today...adulting is so hard." or "I can't adult today." You're a freaking adult, you don't get extra credit for doing things that every other person has to do. That's called life and responsibility, and you shouldn't be surprised by it.